The present invention relates to metallic ink based writing instruments and, more particularly, to metallic ink compositions for wick type writing instruments.
Currently, metallic ink writing instruments are enjoying great popularity. These are almost entirely in the form of a conventional style marker currently called a valve action marker (see FIG. 1). From the diagram, one can see that this is a complex device involving elaborate assembly. The valve action marker also involves shaking back and forth and then depressing, or pumping, the nib several times before ink will come down. As one can see, this is a rather cumbersome process.
Historically, metallic pigments have a large particle size greater than 20 microns; therefore, passage through a wick-style marker has not been possible. Instead, a valve-action marker is constructed with two steel balls in its ink chamber and a spring mechanism at the front in contact with the nib or tip. Since the specific gravity of the aluminum pigment is greater than water, it tends to settle rapidly. This is overcome by shaking back and forth, thereby re-mixing the aluminum particles in the ink. The pumping action on the paper forces the large particle aluminum pigments through the tip by applying pressure through the tip, thereby, producing ink and making writing possible.
Related conventional art includes U.S. Pat. No. 5,013,543 to Mercado; U.S. Pat. No. 5,219,560 to Kazuhiro; U.S. Pat. No. 5,106,881 to Hiroshi; U.S. Pat. No. 4,761,277 to Valdes; U.S. Pat. No. 4,872,905 to Bourne and U.S. Pat. No. 4,604,139 to Shoi, the contents of which are incorporated by reference herein. Regardless, the prior art has not delivered to date a wick-style marker which can deliver metallic pigments, i.e. inks, in writing instruments. As a result, metallic ink writing instruments have been more expensive, more complex to build and maintain, less reliable and have not fully realized their potential.
The general object of the present invention is to provide metallic ink compositions that work reliably in wick type writing instruments.
The foregoing and other objects of the invention are realized by the present invention which shows how one can overcome the aforementioned drawbacks of the prior art using a comparatively inexpensive wick-style marker that works by capillary action eliminating a costly assembly process.
The objects of the invention are achieved by mainly utilizing:
1. A small particle size aluminum dispersion less than 12 microns;
2. an anti-settling agent to keep aluminum flakes in suspension;
3. a densely packed highly porous polyester fiber filler;
4. a highly porous oriented polyester fiber nib with many channels;
5. a non-volatile humectant; and
6. a sub-micron colored pigmented dispersion.
This invention will work for a conventional simple wick-style marker that carries a cylindrical shaped reservoir (filler) that absorbs the ink and transports it to a porous oriented fiber nib that feeds on the filler by capillary action (see FIG. 2).
The invention results in a minimum of metallic particles settling out. The marker can be stored either vertically or horizontally; overcoming a traditional problem associated with pigmented ink systems. This wick-ink system, when filled into the writing device (FIG. 2), will also lay-down a thick opaque line capable of being seen on both black and white surfaces.
Traditional inks that work with pens (FIG. 2) cannot write on black paper since they are translucent, therefore, this market has been occupied by the valve-action marker of FIG. 1 which permits the flow of large particle size pigments. This invention solves this problem in a wick-style writing instrument (FIG. 2) that is user friendly and much simpler, not to mention a cheaper alternative.
The present invention is based on the startling discovery that based on the disclosed, specific ink formulation, a writing instrument can be made that carries a cylindrical shaped reservoir which feeds into a fiber nib by capillary action and remains for extended periods without settling out or blocking the nib or tip. This invention also eliminates the use of an expensive valve type marker.
Thus, an object of the invention is that a single wick-type pen can be used to write on both black and white surfaces and achieve a metallic almost iridescent appearance.
Another object of the invention is a pen that may possibly be used for decorative poster work on both black and white surfaces.
A further object of the invention is the ability to write on human skin to achieve decorative effects similar to temporary tattoos, with an intense opaque metallic look, and washable with soap and water.
Still further, an object of this invention is to attain, by changing the permanent binder to a temporary one, a damp erase or dry erase writing instrument that can be made to write on black and white melamine, porcelain and all non porous boards.
The invention composition includes water as a carrier, an acrylic resin in solution as a binder although a polyvinylpyrrolidone polymer can be substituted to make temporary inks, a pigmented dispersion as a coloring agent, a unique aluminum dispersion of particle size 1 to 12 microns, a surfactant to reduce surface tension, an anti-settling agent to suspend aluminum particles along with a preservative, and a pH adjuster in the form of an amine.
The components of the writing instrument utilized in this invention are of some importance. The polyester filler, or reservoir chosen, must be densely packed and porous to allow flow of aluminum particles and at the same time keep settling to a minimum. Polyester fiber is chosen because it is non-reactive and very porous. The tip, or nib, of the writing instrument must be a porous, oriented polyester nib that has many channels to allow aluminum pigments to pass freely. Many other types of fibers will filter the aluminum and only allow the colored pigment to pass through, thus creating a non-metallic appearance.
One additional detail should be noted about this invention. Dyes are not used in this composition. This is because dyes wash away easily, they do not provide bonding to the aluminum pigments and are more of an outline as described in U.S. Pat. No. 4,604,139.
This invention utilizes a permanent and semi-permanent opaque metallic ink, which may display iridescent qualities depending on the surface written onxe2x80x94black or white.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.